A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-energy exhaust gas flow. The high-energy exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes first and second compressor sections, and the turbine section includes first and second turbine sections.
A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall propulsive efficiency of the engine. In such engine architectures, a shaft driven by one of the turbine sections provides an input to the epicyclical gear assembly that drives the fan section at a reduced speed such that both the turbine section and the fan section can rotate at closer to optimal speeds.
Lubrication systems for turbine engines are typically sized and operated to continually provide a minimum level of lubricant flow and pressure to the various structures and portions of the engine. The minimum level of lubricant flow and pressure is typically based on maximum lubricant demand conditions such as during maximum thrust conditions during take-off. Other operating conditions may not require lubricant at such high levels of lubricant pressure and flows. Excess lubricant flow can reduce efficiency and insufficient lubricant flow and pressure can increase wear on components.
Although geared architectures have improved propulsive efficiency, turbine engine manufacturers continue to seek further improvements to engine performance including improvements to thermal, transfer and propulsive efficiencies.